This invention relates to the programmed control of heating and cooling systems utilizing one or more programmed microprocessors. In particular, this invention relates to the manner in which the programmed control in the microprocessors interfaces with various elements in the heating and cooling systems.
Programmed control of heating and cooling systems using microprocessors is well known. The programmed control normally includes stored instructions which either send or await the receipt of communications from various elements in the heating and cooling systems. These elements include temperature sensors, control valves, as well as fan and compressor motors. In each instance, an input or output (I/O) channel associated with the microprocessor is specifically identified in the software for use in communicating with a particular element. When communication is to take place, the element either receives an output signal or transmits an input signal over the designated I/O channel. The programmed control within the microprocessor proceeds on the assumption that all control functions are being properly executed by the elements.
The above described program control can pose problems when making any changes to the software residing in the microprocessor. In this regard, one must maintain an accurate accounting at all times of the I/O channel assignments to the elements when making any changes or revisions to the software.
One must also be careful when attempting to use the program control for what is believed to be a similar heating and cooling system having a similar configuration of elements. In this regard any differences in the elements in the second system must be carefully noted in the instructions for these particular elements.